Maintenance and extraction of poles

ABSTRACT

An apparatus for excavation of earth around a pole embedded in an earth surface comprises a hollow auger in the form of a cylindrical drum with a helical flight about the outer wall thereof. The hollow auger is constructed in two halves to enable movement between an open position and a closed position embracing the pole. The hollow auger is rotatably journalled in a support frame and is driven by a drive motor engaging a spur gear around the upper position of the auger. The support frame is slidably mounted on a frame to enable extension and retraction of the auger.

This invention is concerned with maintenance and extraction of polespiers and piles from earth surfaces.

In particular, this invention is concerned with maintenance andextraction of timber, concrete and steel poles and like supports forpower and telephone transmission lines, fence posts, building supportpiers, marine pilings and the like.

Timber power and telegraph poles are prone to deterioration as a resultof fungal and termite attack, particularly in the region extending fromthe point of emergence form a ground surface to about 600 mm below theground surface. Concrete and steel poles may also be subject todeterioration as a result of corrosion in a similar region. Marinepilings typically deteriorate over their exposed normally wettedsurfaces.

In order to maintain such poles, it is necessary to excavate the eartharound the pole to a depth of about 600 mm to inspect the pole conditionand to apply timber preservation and protective composition. Typically,such excavations are carried out manually with a pick and shovel.

When it is desired to remove or replace a telegraph or powertransmission pole which is damaged as a result of, say, a motor vehicleaccident, termite or fungal decay, it is necessary to excavate asubstantial amount of earth from around the pole to facilitate removal.A typical method of extracting piles is described and illustrated inAustralian Patent No. 524678 which is concerned with a method forsleeving damaged poles. The main disadvantage of this method is that anew or repaired pole is replaced in a ground surface surrounded by asubstantial volume of disturbed and uncompacted earth. This maynecessitate the use of additional equipment to compact the disturbedearth.

To facilitate extraction of a submerged marine piling, it is commonpractice to excavate around the base of a piling member by means of ahigh pressure water cannon.

All of the prior art methods of maintaining and extracting poles,pilings etc are heavily labour intensive and/or require specialisedheavy equipment to carry out these functions.

It is an aim of the present invention to provide a method and apparatusfor excavation around poles, pilings and the like embedded in an earthsurface and to facilitate extraction of those poles, pilings and thelike if so required.

As used herein the expression "pole" is intended to embrace all types ofpoles embedded in earth surfaces on dry land or a sea bed and includes,power poles, telegraph poles, fence poles, piers, pilings and the like.

According to one aspect of the invention there is provided an apparatusfor excavation of earth about a pole embedded in an earth surface, saidapparatus comprising:

a support frame;

a substantially cylindrical earth excavation member rotatably journalledin said support frame;

drive means to rotate said earth excavation member; and,

means to advance said earth excavation member in a desired direction.

Suitably said support frame is adapted for mounting on a mobile vehicle.

Preferably said apparatus includes orientation means to selectivelyorientate said earth excavation member for earth excavation in apredetermined direction.

If required said apparatus may includes stabiliser means to stabilisethe apparatus during excavation.

Suitably the earth excavation member comprises a cylindrical drum withat least one earth working element located on the outer periphery ofsaid drum.

Preferably said at least one earth working element comprises a helicalflight.

Preferably said helical flight includes a cutting edge at its leadingfree end.

If required one or more cutting edges may be associated with a leadingportion of said drum.

Preferably said drum comprises a continuous inner wall surface.

If required scraping means may be provided to scrape excavated earthfrom said helical flight adjacent a trailing end thereof.

Preferably said earth excavation member is comprised of two or moreportions movable between an open position and a closed position toembrace an upright pole for earth excavation therearound.

Preferably said earth excavation member includes a drive portion and aremovable excavation portion.

Preferably said drive means comprises at least one drive motor adaptedto engage a drive portion on said earth excavation member.

Suitably said drive means comprises a rack and pinion drive mechanism.

Preferably said rack and pinion drive mechanism comprises a rack memberextending about the periphery of said drive portion.

The means to advance said earth excavation member in a requireddirection may comprise a carriage associated with said support frame,said carriage being selectively advanceable or retractable by anysuitable means.

Alternatively said means to advance said earth excavation member maycomprise pole engaging drive means associated with said support frame.

Preferably said apparatus is associated with a mobile vehicle includinghoist means to extract a pole from a ground surface after excavation.

According to another aspect of the invention there is provided a methodof excavation of earth about the base of a pole embedded in an earthsurface, said method comprising the steps of:

surrounding said pole with an earth excavation member comprising asubstantially cylindrical drum having a helical flight located about theouter peripheral surface of said drum;

rotating said drum; and,

advancing said drum into said earth surface at a predetermined rate to apredetermined distance to effect removal of earth from around said pole.

Preferably said earth excavation member is associated with a mobilevehicle including a support frame in which said drum is rotatablyJournalled and retractable means to advance said support frame in adirection of excavation.

Suitably the pole may be extracted by pole extraction means afterexcavation about said pole.

In order that the invention may be more fully understood, reference isnow made to preferred embodiments illustrated in the accompanyingdrawings in which:

FIG. 1 illustrates a side elevation of a tractor mounted excavationapparatus.

FIG. 2 illustrates a partial top plan view of the apparatus of FIG. 1.

FIG. 3 illustrates a part cross sectional view of the apparatus throughA--A in FIG. 1.

FIG. 4 illustrates schematically the excavation apparatus mounted on amobile vehicle with a pole excavation hoist.

FIG. 5 shows a further variation of the apparatus of FIG. 4.

FIG. 6 illustrates an adaptation of the excavation apparatus for remotecontrolled excavation of submerged piles.

In FIG. 1 the excavating apparatus 1 is shown attached to the rear of atractor (not shown) and it utilises a source of pressurised hydraulicfluid from the tractor for operation.

Apparatus 1 comprises a tractor mounting bracket 2 with which isassociated splayed stabiliser legs 3 powered by hydraulic rams 4.

Pivotally mounted on bracket 2 is a support bracket 5 to which ismounted a telescopic boom 6. Boom 6 is movable between an extendedoperating position as shown and an upright travelling position byhydraulic ram 7. A hydraulic ram (not shown) is located within outerboom portion 6a to telescopically extend or retract inner boom portion6b. A boom slewing ram 8 is connected to an arm 9 extending transverselyfrom bracket 5.

A tiltable frame 10 is pivotally mounted on the end of boom 6 fortiltable movement about a transverse pivot 11 by means of hydraulic ram12.

The frame 10 is also tiltable about the longitudinal axis of boom 6about pivot 13 and is tiltable by means of hydraulic ram 14.

A support frame 15 is slidably mounted on slide bars 16 and is movablebetween an extended position and a retracted position by hydraulic ram17 mounted on top of frame 10.

Rotatably journalled within support frame 15 is a cylindrical earthexcavation apparatus comprising a drive portion 18 and a removableexcavation portion 19.

Drive portion 18 includes a spur gear or the like 26 extending about theouter periphery of the drive portion 18 and is rotatable by means ofdiametrically opposed hydraulic motors 20, each with drive pinions (notshown) engaging with the spur gear.

The excavating portion 19 comprises a cylindrical drum 21 with a helicalflight 22 extending thereabout. The leading end of the flight is fittedwith a hardened cutting edge.

Drum 21 is attached to the drive portion 18 by bolting together matingflanges 23 on each portion. This enables interchangeability ofexcavating portions 19 of differing diameters and/or lengths ifrequired.

Mounted on the lower edge of drum 21 are additional cutting edges 24 toassist in loosening the earth for collection by the auger flight 22 whenin use.

Support frame 15, drive portion 18 and excavating apparatus 19 are eachformed from generally hemicylindrical halves and are adapted formovement by a hydraulic ram (not shown ) between an open position toenable a pole to be embraced and a closed position around a pole foroperation. Drum 21 thus comprises two hemicylindrical halves 21a and21b.

The operation of the apparatus will now be described.

The tractor mounted apparatus is positioned adjacent a pole (not shown)about the base of which excavation is desired. Stabiliser arms 3 areactuated to stabilise and level the tractor.

The hydraulic ram (not shown) operable to open and close excavatingapparatus 19 is actuated to open frame 15 and drive and excavatingportions 18 and 19 respectively. Boom 6 is then extended to position theopen excavation apparatus relative to the pole and then the excavatingapparatus is closed to embrace the pole.

The excavating apparatus is aligned by means of rams 12 and/or 14relative to the pole and ram 7 is then actuated to lower the apparatusto ground level whereupon a pointed support foot 25 penetrates the earthsurface to locate and stabilise frame 10.

Hydraulic motors 20 are then actuated and support frame 15 is thenadvanced towards the earth surface by ram 17. The rate and extent ofadvancement of the excavating portion 19 is controlled by ram 17.

As excavating portion 19 rotates and advances downwardly, earth isremoved from adjacent the embedded portion of the pole by the helicalflight and deposited under centrifugal force around the circularexcavation aperture. If required, scrapers may be employed to removeearth adhering to the helical flight.

Ram 17 is then actuated to withdraw the excavating apparatus and anyearth trapped between the inner wall of drum 21 and the pole then fallsto the bottom of the excavation to expose the normally embedded surfaceof the pole.

The apparatus described above may be utilised to excavate only to apredetermined depth to expose, for inspection and/or treatment purposes,a portion of the pole normally subject to deterioration or alternativelyto excavate around the entire embedded portion to facilitate extractionof the pole.

By employing replaceable auger drum 21 of differing diameters and/orlengths the apparatus is suitable for all pole excavation purposes.

FIG. 2 shows a top plan view of the support frame 15.

Frame 15 comprises two halves 15a, 15b pivotable about pivot 30 betweenan open position and a closed position as shown. A toggle linkagemechanism 31 is operated by hydraulic ram 32 to move halves 15a, 15bbetween an open position and a closed, locked position as shown.

The hemicylindrical drive portion 18a, 18b (to which respective drumportions 21a, 21b are attached) are journalled in frame halves 15a, 15bin such a manner that they are supportably retained in their respectiveframe halves when frame 15 is in an open position.

Brackets 33, 34 respectively mounted on frame halves 15a, 15b includerespective spigots and sockets (not shown) to align frame halves 15a,15b in a closed position.

FIG. 3 shows a part sectional view through A--A of support frame 15illustrated in FIGS. 1 and 2, and for the sake of clarity, certain itemshave been omitted.

Frame 15 comprises a generally annular, hollow box member in which driveportion 18 is rotatably journalled.

Drive portion 18 comprises hemicylindrical wall portions 18a, 18b eachwith semi-annular flanges 40a, 40b mounted at the lower edge thereof.The hemicylindrical halves 21a, 21b of excavating drum 21 (shown inFIG. 1) are removably attached to drive portion by bolting throughsemi-annular flanges 41a, 41b attached to the upper portions of drumhalves 21a, 21b.

Semi annular ring members 42a, 42b and 43a, 43b are located respectivelyadjacent the upper and lower regions of drive portions 18a, 18b.

Mounted on ring halves 42a, 42b and 43a, 43b are semi-annular upper andlower bronze bearing strips 44a, 44b and 45a, 45b respectively. Bearingstrips 44a, 44b and 45a, 45b are located in recesses formed in splitupper and lower annular locating members 46, 47 respectively and suchrecesses form annular bearing grooves to permit rotatable journalling ofdrive portion 18.

Mounted on a step in ring halves 43a, 43b is a diametrically split ringor spur gear forming gear halves 48a, 48b.

A drive shaft 49 of hydraulic motor 20 (not shown) engages with a pinionshaft 50 located in bearings 51, 52 between which is mounted a drivepinion 53 on pinion shaft 50. Pinion 53 engages with the split ring orspur gear formed by gear halves 48a, 48b to cause drive portion 18 torotate in support frame 15.

It will be seen that the manner of mounting bearing strips 44a, 44b and45a, 45b permits support frame 15 to be pivoted to an open positionwhilst still supporting the drive and excavating half portions of driveportion 18 and excavating portion 19 respectively.

FIG. 4 shows schematically an alternative embodiment of the invention.

In this embodiment an articulated vehicle 60 with a central pivotal axis61 has mounted on the front portion thereof an earth excavatingapparatus 62 of the type generally shown in FIGS. 1-3. The excavatingapparatus 62 is slidably mounted on a track which in turn is tiltableabout pivot 63 between an upright operating position as shown and aninclined travelling position.

A telescopic boom hoist 64 mounted on the rear portion of vehicle 60includes a clamp mechanism 65 to grasp pole 66 to enable excavation ofearth from around the portion of the pole embedded in the earth. Afterexcavation is completed, the excavating apparatus 62 is retracted andthe excavating drum 67 is opened to enable the vehicle 60 to move awayfrom the pole whilst extending boom 64 to maintain the pole 66 in asteady upright state.

With the entire embedded portion of the pole now exposed, a completeinspection may be carried out with the pole safely stabilised and ifrequired, the normally embedded portion may be treated with apreservative, anti-fungal composition etc.

If, due to severe deterioration, the pole 66 needs replacement, the boomhoist 64 may then be actuated to extract the pole 66 from the ground,load it upon a transport vehicle and reinsert a new pole.

FIG. 5 shows yet another alternative embodiment of the apparatus shownin FIG. 4.

In this embodiment a vehicle 70 includes a tiltable track 71 pivotedabout pivot 72 between an upright operating position as shown and atilted travelling position (not shown) by means of hydraulic ram 73.

Slidably mounted on track 71 is an excavating apparatus 74 of the typehereinbefore described and a clamp means 75 also slidably mounted ontrack 71.

With the apparatus shown a pole may be excavated whilst supported byclamp means 75 and subsequently extracted from the earth. Track 71 isthen tilted to a travelling position to enable transportation of theextracted pole.

FIG. 6 shows a further embodiment of the invention adapted to excavateabout the embedded portion of a marine piling or the like.

The apparatus 80 comprises an excavating portion 81 of the typegenerally described about with a frame or housing 82 mounted on thesupport frame 83.

The frame or housing 82 includes retractable idler rollers 84 adapted togrip the piling 85 and to align the excavating portion 81 therewith.

An advancing means 86 in the form of a toothed drive wheel or trackmechanism is driven by an hydraulic motor to selectively move theapparatus 80 up or down the piling 85.

In this embodiment, the apparatus may be positioned around a piling andremotely operated to excavate around the embedded base thereon tofacilitate extraction of the piling. It will be readily apparent to askilled addressee that an apparatus according to the invention forexcavation about a submerged piling may be remotely operated from aplatform on the piling or from a nearby floating vessel.

Similarly the apparatus may be attached to a floating vessel in a mannersimilar to the embodiments illustrated in FIGS. 1, 4 or 5 or any otherconvenient manner.

We claim:
 1. An apparatus for excavation of earth about a pole embeddedin an earth surface, said apparatus comprising:a support frame; asubstantially cylindrical earth excavation drum having at least onehelical flight on an outer periphery of the drum, said drum beingrotatably journalled in said support frame; drive means to rotate saidearth excavation member; and advancing means to advance said earthexcavation member in a desired direction, wherein said support frame andsaid drum are each comprised of two or more portions movable between anopen position and a closed position to embrace an upright pole for earthexcavation.
 2. An apparatus as claimed in claim 1 wherein said supportframe is adapted for mounting on a mobile vehicle.
 3. An apparatus as inclaim 2 wherein said apparatus includes a tilting mechanism toselectively orient said drum for earth excavation in a predetermineddirection.
 4. An apparatus as in claim 3 including ground engagingstabilizers to stabilize the apparatus during operation.
 5. An apparatusas in claim 1 wherein said drum includes a plurality of cutting edgeslocated in a lower end of the drum.
 6. An apparatus as in claim 1wherein said drum, when in a closed position, comprises a substantiallycontinuous inner wall surface.
 7. An apparatus as in claim 1 whereinsaid earth excavation drum includes a drive portion and a removableexcavation portion.
 8. An apparatus as in claim 1 wherein said advancingmeans comprises a carriage coupled to said support frame, said carriagebeing movable between an advanced position and a retracted portion. 9.An apparatus as in claim 1 wherein said advancing means comprises poleengaging drive members coupled to said support frame.
 10. A method ofexcavation of earth about a base of a pole embedded in an earth surface,said method comprising the steps of:surrounding said pole with an earthexcavation member comprising a substantially cylindrical drum having ahelical flight located about the outer peripheral surface of said drum;rotating said drum; and advancing said drum into said earth surface at apredetermined rate to a predetermined distance to effect removal ofearth from around said pole.
 11. A method as claimed in claim 10 whereinsaid pole is surrounded by said earth excavation member by locating saidearth excavation member over the top of said pole and moving the earthexcavation member to the base portion of said pole.
 12. A method asclaimed in claim 10 wherein said earth excavation member comprises atleast two portions movable between an open position and a closedposition wherein said excavation member is moved, in an open positiontowards said pole and subsequently closed to embrace said pole prior toexcavation therearound.
 13. A method as claimed in claim 10 wherein saidpole is surrounded by an earth excavation member having at least twoportions movable between an open and closed position, the method furthercomprising the steps of positioning the earth excavation member in anopen position adjacent the pole and closing the at least two portions tosurround said pole prior to rotation of said drum.
 14. An apparatus forexcavation of earth about a pole embedded in an earth surface, saidapparatus comprising:a support frame; a substantially cylindrical earthexcavation drum having at least one helical flight located on an outerperiphery thereof, said drum being rotatably journalled in said supportframe; drive means to rotate said drum; advancing means to advance saidexcavation member in a desired direction, said support frame and saiddrum each having two or more portions movable between an open positionand a closed position to embrace an upright pole for earth excavationtherearound, wherein said support frame being mounted adjacent an end ofboom assembly pivotally attached to a mobile vehicle, said support framebeing selectively tillable to orient said drum relative to said poleduring excavation of earth from therearound.